| We have investigated the effects of the microstructure and mechanical properties with V content and heat treatment on the rapidly solidified V added Fe-13 Mn-1.2C steel strips which were produced by a twin roll melt-quenching method. Regardless of the V content, solidification process typically took place by primary austenite formation and then the residual liquid phase formed austenite by massive transformation. In melt-quenched, the austenite to ferrite transformation was suppressed, resulting in only austenite. As the V content increased, the equiaxed structure region increased and the secondary dendrite arm spacing became a little wider. With the increase in V content, the refining of austenite grain size after heat treatment was accelerated because the increase in the formation of carbides suppressed the grain growth. As 0.2%Y.S. was increased with increasing V content, a relation between it and grain size as a function of V content can be expressed as the following equation. 0.2% Y.S.(㎏/㎟)=22.05+7.4/√D The mechanism of the large strengthening effect of V on the 0.2% Y.S. was considered to be attributable to the grain refining by V addition and the large increase of Petch constan |
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